


Stranded

by MorallyGray



Category: Supernatural
Genre: Alpha Castiel, Alpha Sam, Alpha/Beta/Omega Dynamics, Alpha/Omega, Big Brother Sam Winchester, M/M, Mating Cycles/In Heat, Mpreg, Omega Dean, Other sensitive tags in the end notes, Sibling Incest, endgame sam/dean/cas, pretty much FOD, unwilling incest in the beginning on both parts
Language: English
Status: In-Progress
Published: 2015-03-20
Updated: 2015-03-20
Packaged: 2018-03-18 18:21:49
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,433
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3579366
Author URL: https://archiveofourown.org/users/MorallyGray/pseuds/MorallyGray
Summary: <blockquote class="userstuff">
              <p>Sam and Dean are stranded on a remote island off the coast of Alaska. Luckily, it's summer, so they don't have to worry about exposure and they have enough food for a week or more. What they don't have are Dean's hormone regulators or Sam's suppressants. As they sit on the beach, Sam's little brother only starts to smell better and better and he hates himself for it.</p>
            </blockquote>





	Stranded

**Author's Note:**

> Sam will be pretty OoC, Cas will be too. So fair warning. 
> 
> Sibling incest happens more publicly in this AU, but it's still frowned upon by most people.

Sam remembers when he was nineteen. That was the first time Dean sweated this way musky and sweet. Now his cheeks are stubble-covered and in the firelight he can see where Dean will eventually have wrinkles with his eyes shut in pain. Then, over ten years ago, Dean was maybe five and a half foot if he was lucky. He was still gangly like a little deer sitting on his camo bed spread with his first little buck’s head hanging on the wall above.

  _When he came home from work he found Dean that way in his room, on his bed with his knees drawn up to his chest and his forehead against them. His pupils dilated when he looked up. His cheek had dented where he was gnawing at the inside. Even with the patch behind Sam’s ear, the smell made his mouth water._

_“You okay, Dean?” he asked._

_Dean shook his head with his hands buried in his hair again. “It’s driving me fuckin’ crazy.”_

_Dean was only thirteen. He shouldn’t be cussing, but with the smell coming off of him, Sam didn’t get on to him._

_“I’m sorry, Bubba,” he said. He glanced back down the hallway when he heard his dad moving around in the living room, probably just arranging himself on the couch, but it made him tense. “Go on get in my bed.”_

_“I’m gross right now.”_

_“You’re alright. I’ll get it all washed up after.”_

_“Okay,” Dean said, but he didn’t move to get off the bed and his skin turned red._

_“I’m going to go take a shower,” Sam said and moved out of the doorway so Dean could get out of the bed without showing off the hard-on Sam knew he had. He showered as quickly as he could with still rubbing one out, letting his cum go down the drain and take away the little edge the patch wasn’t taking care of._

_When he got out, he went into his room with the towel around his waist. Dean was in his bed buried up to his eyes in the blankets although his skin was wet. Sam smiled slightly when he saw Dean smelling the sheets. His skin turned redder and it was sweet. It wasn’t Dean’s fault._

_“Close your eyes a minute,” he said._

_When Dean did, Sam pulled open his dresser drawer and pulled on a pair of underwear then sleep pants and a t-shirt. He usually just slept in his underwear, but there wasn’t any reason to push things. He flipped off the light then got into his queen-sized bed. He felt Dean’s heat radiating against him, like he had a fever and he kind of did._

_He rolled onto his stomach and closed his eyes, the patch making it easier to ignore the smell. Beside him, Dean kept rolling and shifting._

_“Did you take your pills?” Sam asked._

_“I don’t know where they went,” Dean said, flopping onto his back again._

_“Give me a minute,” Sam said and he got back up. He slipped out of his bedroom and went to the bathroom. He opened his drawer and pulled out a bottle of pain pills. He dumped out a few and found the suppressant pills he was looking for mixed with them. Then he went to the kitchen and filled a glass with ice water. His dad was on the couch, staring at the TV. From here he could see the hard-on. With an exhale he moved out of the room and back into his dark bedroom. He handled the pills to Dean and the water. Dean sat up and drank._

_Finally, he handed back the glass and Sam got back beneath the blankets._

_“Why can’t I sleep in my room?” Dean asked quietly._

_Sam smiled weakly, laying back on his stomach and now Dean was laid the same way looking at him. He didn’t want to tell him why, so he brushed Dean’s too long hair back from his forehead. After this he needed to take him to get it cut when Dean could be back in public._

_“I just feel safer with you being close.”_

_He didn’t say that he was worried about their father or their other brother, Adam, going into Dean’s room. Their dad was weak, he may not even smell Dean strongly enough to matter, but Adam would. He would hate to have to break Adam’s neck, but he would._

_“When is it going to stop?” Dean asked._

_Sam kept brushing his thumb over Dean’s hair in front of his ear. It was so soft and normally he would’ve stopped by now or Dean would’ve brushed him off, but he just wanted to make him feel better._

_“Those pills’ll kick in in a minute.”_

_“No, when will it all stop?”_

_“Three, maybe five days,” he said. “I don’t know, Bubba. I’ve never gone through it.”_

_“Asshole,” Dean said and flopped onto his back. He slid his hands over his face and groaned. “Fuck my life.”_

_Sam laughed, “You’ll be alright.”_

_“When can I actually go take care of it?” he asked and with the heat pouring off him, Sam didn’t even see his coloring change. Dean’s hand went under the covers and pulled at his boxers._

_“You’re still just little,” Sam said._

_“Cas hasn’t hit yet.”_

_“Bud,” he said carefully. “Cas’s not going to go through the same thing.”_

_“You don’t know that yet.”_

_He patted Dean’s chest, burning hot. He knew it from the first time he met Cas that he would be an alpha. Just like most everyone who met Dean knew he was an omega. Right now it would seem like a bad thing that Cas wasn’t going to go through the cycles, but later it wouldn’t. Cas would hit soon, but it would be different. Sam was slightly surprised that he hadn’t gone into it before Dean, so their bodies could be ready at the same time, although they were still too young to do what their hormones wanted them too. Still if you got them within a few yards of each other right now, Dean and Cas’s status of childhood best friends was going to escalate quickly._

_As much as he knew it was going to happen, Sam wanted it to be years, not months, or days. Shit, he could see Dean counting minutes, seconds. Still he felt better that he had taken off for the next week. It wouldn’t be happening on Dean’s first cycle, on this cycle, when he still had the softness on the swell of his cheeks and around his belly. He still watched cartoons when no one else was home and even though there was only five years between them, he was still Sam’s sweet baby brother._

_Hormones weren’t going to change that._

Now, Dean sits on the other side of the fire and holds his torso in. He’s shaking and Sam wants to go hold him, but can’t because his patch is giving out and Dean smells so good. They’ve been stranded here for over three days and Dean is hitting hard.

“I miss him,” Dean chokes. “I just fucking want Cas.”

And Sam knows he does. He’d give anything if he could just let Dean be home with Cas. Instead of sitting across from his little brother with his heart breaking and his mouth watering, he’d be calling to make fun of Dean in a few days for shutting himself up with Cas for a week straight. He would be laughing at the cocky, loving expression Cas would be giving Dean for the weeks after, like he was the shit for getting him into bed and making him happy.

“I’m going to go so you can do what you need to,” he says gently and he hates that he’s having to leave Dean while he’s upset.

Dean shakes his head and his hair is so sweaty it’s stuck to his head. “I can wait. You need the fire.”

Sam laughs shakily and gets up. “I can build my own fire.”

Dean looks up and his brown eyes are so wet. Even with the smell, Sam grits his teeth and goes toward him. He tries not to breathe and kneels down in front of Dean. He puts his hands on his face and rubs his thumbs forward and back. The lump in his throat is aching and Dean is shaking. His skin is so hot and Sam knows that Dean hasn’t been without Cas during a cycle since he was seventeen and Cas was sixteen. Now, Dean is twenty-seven and Sam can see his heart breaking, the panic, and the pain.

“We’ll get back home as soon as we can,” he says and he’s crying too, because he can’t not when Dean is.

“Fuck it hurts,” Dean says. He never talks about pain, but Sam can see the rash breaking out over his reddened skin without the medication to suppress it.

“I know,” he says and even seeing the color makes him want to do things that he doesn’t want to. He’s got the right genes to take the color away and make Dean stop burning up and stop hurting. He hates himself.

“I’m just going to be a little ways down,” he says and leans forward to kiss Dean’s cheek. The stubble-roughened skin burns his lips. “I’m so sorry I can’t make it better,” he says and hugs Dean tightly. Dean doesn’t hug him back, but groans between gritted teeth.

He pulls away and gets up. He grabs some of the kindling from their destroyed boat and walks away. The further he gets from the fire, the less he smells Dean. He doesn’t stop walking until it’s faint beneath the sea salt and moist soil. He sits on the soil, sand, and rocks. He doesn’t bother with a fire, his skin is burning too. He lays on his back and looks up at the sky and breaths through his mouth.

He makes himself think about Cas. Dean’s husband and Sam loves him like a brother. He remembers the first time Dean came home from school after getting off his first cycle. He had smiled so wide when he came in the door.

_“What’s up?” he asked, smiling because Dean was smiling._

_“Nothing,” Dean said._

_“Looks like it,” he said, but he let it drop and went to pull some meat from the freezer. “What’d you want for dinner?”_

_He found out what Dean was grinning over a week later when he went to pick him up at school after detention. Apparently Cas had detention too, because they were both on a bench outside the front doors. Dean was turning red and Cas was kissing the corner of his upturned mouth then they kissed fully on the lips and Sam honked the horn. Both of them jerked like they’d been shocked and Sam laughed._

_When Dean reached the truck, he was still red and so was Cas just behind him._

_“Can you give Cas a ride home?” Dean asked._

_“Sure, no kissing in the truck, though,” he said and both boys turned redder. He stifled a grin as Dean slid in beside him and Cas sat on the far side of the bench seat._

_“Thanks,” Cas said._

_“No problem.” And as soon as Cas got in, he smelled the change. Dean was thirteen. Cas was twelve. They were so young, but when they kept stealing looks at each other, they didn’t look young._

_Then, it scared Sam._

_When he pulled up outside of Cas’s grandparents, Cas said thanks again. Then he and Dean mumbled a few things to each other that he tried to ignore, then he heard the soft sound of them kissing._

_“Hey,” he said and gave Cas a push. “Get outta here you little shit.”_

_Cas knew him enough to know when he wasn’t mad and he smiled at Sam then Dean, squeezing his hand and getting out._

_“See you tomorrow,” Cas said._

_“Yeah,” Dean said. “I’ll call later.”_

_“Okay,” Cas said and he grinned again before shutting the door._

_When he pulled out of the driveway, he glanced toward Dean, who moved into Cas’s spot._

_“When did he hit?” he asked, trying to sound casual._

_“The same time as me,” Dean said and his smile looked like it would split his face._

_“Don’t you two be trying anything,” Sam said. “It’s cute and all that shit, but you’re both still babies.”_

_“I know,” Dean said._

_The cycles from then until Dean turned seventeen were hell. He had to take off work to keep Dean under control and nearly comatose on medication for a week every six months. He didn’t let Cas come around much during those times. Still, the look Cas got when he was near Dean, when he was sweating and aching, was better than the hungry looks their dad and Adam gave him. So when Dean was in, Sam kept him close, normally in his room, away from the other alphas in the house. The pills made Dean tired and sweet, so most times they ended up on Sam’s bed with him cuddling Dean, to give him physical contact, until he was old enough to be with Cas or someone like him._

_When Sam walked into his house, where he and Dean were living, when Dean was seventeen, he was more relieved than irritated when he took one breath and realized Dean was in cycle, Cas was there, and by the smell of it, they’re was going to be a whole lot less angst going on around the house._

_He went and stayed with his girlfriend for a week until Dean finally called him._

_“Hey,” Dean said when Sam answered the phone._

_“Are you guys done yet?”_

_“Yeah,” Dean said. “I’m sorry.”_

_“I’m not really mad,” he said. “I’ll be home in an hour, so throw the sheets in the washer and get a shower.”_

_“We already did,” Dean said._

_“Are you feeling better?”_

_Dean laughed and it was quiet. “Yeah, I’m just tired.”_

_When he got there, the house didn’t smell like sex and the boys were on the couch. Cas was holding Dean and they were still gangly and roughly the same size._

_“Sorry, Sam,” Cas said with a slight frown, but even with that the way he held Dean made it clear that he’d do it all over again._

_He waved him off and sat in the chair his ass had missed. “What do your parents think you’ve been doing for the last week?”_

_“I don’t really remember what I told them,” Cas said, turning red._

_Dean was already half asleep in Cas’s arms, but he smiled. “They didn’t believe you.”_

_“Nah I don’t think so either,” Cas said and he kissed Dean’s hair._

_It was sweet, sickeningly sweet and two teenage boys shouldn’t be able to look at each like that, but they were. Dean fell asleep against Cas with a familiarity they hadn’t quite managed before. He and Cas talked while Dean slept, about football, college, NFL and the high school team._

_When Dean woke up, he was still blurry-eyed. Sam marked it up to him being Dean’s big brother and not his dad that he was willing to let Cas stay the next few days if he hadn’t already been called to get home. Dean would be sleepy for the next few days and if they were old enough to have their own house, Cas would be taking care of him. He saw the want on Cas’s face to take care of him and the little streak of defiance in his eyes at having to leave when Maggie called again. Sam left the room before Cas left. He heard them mumbling to each other through the thin walls and when he finally came in fifteen minutes later, Cas was kneeling in front of the couch where Dean was laying. A blanket was over Dean and a new glass of water beside him with a sandwich._

_“I love you,” Dean said quietly with his eyelids still heavy._

_“I love you more,” Cas said and kissed his cheek. “I’ll text you.”_

_“Okay,” Dean said and Cas kissed him again._

_Finally, Cas got up and brushed Dean’s cheek whose eyes were already closed. Cas hugged Sam by the front door._

_“I’m sorry we jumped the gun,” Cas said._

_“I’m proud you guys waited this long,” Sam said and patted Cas’s back. “Take good care of him.”_

_“I will,” Cas said and at sixteen, he had all the confidence of a man when he said it._

And Cas always had.

Finally, he closes his eyes and he thinks about his wife. She was like Dean, an omega and he loved her. It still hurt to think about her, how sweet she’d been, how soft and warm. He didn’t normally, but now it’s either that or give into biology and think about Dean. So he takes down his jeans, pushes them low, pulls off his t-shirt and rubs himself. He comes into his hand and it doesn’t help.

After that he goes to the waterline and scrubs himself. Then he lays down in the sand and closes his eyes. He doesn’t think he’ll be able to sleep, but somehow he does and he doesn’t realize he has until he smells heat, so close he can feel it.

He’s afraid to open his eyes, because he feels Dean’s mouth against his neck. The shiver gives him away and Dean’s tongue touches him. He is so hot. If Sam didn’t know that people didn’t die from unrequited cycles, he would think Dean was. This close, his scent is so elevated, so mouth-water it’s stifling.

“I can’t do this, it feels like I’m dying,” Dean says and puts his arms around him.

“Dean, I can’t,” he says and tries to pull away.

“I tried,” Dean says and Sam hears him crying, he smells the tears and they’re only putting out more hormones like they’re supposed to. His sweat is putting out more. His beautiful, warm, slick skin. Dean’s hand trembles when he touches him.

“I can hold you,” he says.

Dean doesn’t answer, but Sam rolls on his side and pulls Dean up to him. When he does, his nose grazes over Dean’s neck, above his pulse and he wants to run his tongue over it. He almost does, Dean angles up his chin and waits. In the faint moonlight, he sees Dean’s eyes have glazed. He’s sliding. He’s not Dean right now. He’s a cycle and he’s in pain, so much that he can barely breathe. Everything in Sam says he can make it better. He can lick the burning skin and make it tan again.

Then Dean’s hands are at his own belt and he’s undoing his jeans. Sam grabs his wrists, but Dean groans weakly. He hates and thanks God that Dean is too far gone to hear the noise from himself, to understand what he’s doing and what he’s asking.

“Please,” Dean says, pressing up to Sam’s neck, inhaling with his breath moist.

His breath catches and he breaths through his nose. It’s only two days in. Dean can’t do five more days of this, because tomorrow will start the worst of it. Squeezing his eyes shut, he brings his mouth down hard on Dean’s.

This is his baby brother. He protected him from their own family when he was young. He tried to be a good parental figure and keep Dean and Cas apart until they were old enough to handle each other.

He loves him only second to his daughter, so he squeezes his eyes shut and loves Dean in the way he needs. He kisses Dean’s shoulder and runs his fingers through his hair the way he’s seen Cas do in passing and when Dean cums under his hand, he says Cas’s name.

And that’s the way it should be.

After when he’s spooned to his brother, Dean cries, and he rubs his chest and stomach and tries to think that it’s not so much different from when he held Dean when he was younger. He wishes he were just holding him. That he didn’t know what it felt like to have Dean contract around him.

But Dean’s skin is cooling. He isn’t shaking anymore. In an hour, maybe sooner or later, they’ll have to again and again and again and again and he tries not to think about it. This is Dean and he would kill for him. He would give him anything.

And he never thought it could hurt so badly.

**Author's Note:**

> If you liked it or want more, comments and kudos are always good to have. :)


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